feat: enable CPU throttling with --cpuThrottle flag

[goooseman]

Feature description

To get more accurate results for comparison it is a good idea to run Chrome with 4x-8x CPU throttling. This way the results will be less influenced by other processes running on the same machine.

This PR adds a special --cpuThrottle which is 1 by default not to change the default behavior. User can set it to any number value (e.g. --cpuThrottle 4) to enable CPU throttling.

PR description

• New CLI flag is added
• New options argument is added to ReactBenchmark
• New test is added to E2E tests (test/cli.js) to make sure this option works correctly
• Docs and typescript definitions are updated

P.S. I was using this project for my personal needs and I have much more changes to contribute in the future, such as:

• Testing performance not until component is rendered, but until onReady callback is called (useful for async tests)
• Measuring not only CPU, but also RAM consumption
• Measuring network consumption
• Adding configurable delay between tests to give Chrome some time to cooldown
• Optional rendering to DOM instead of in-memory rendering which is used right now

[goooseman]

@Rowno ping ping 🏓

[goooseman]

@Rowno lets merge it? 😉

[Rowno]

It looks like your new unit test is failing consistently in CI on master.

[goooseman]

@Rowno checking...

[goooseman]

@Rowno I see it is running right now, waiting for the tests to fail

BTW, don't you think we should enabled CI also on PR, not only in master branch? That can potentially save from such situations to happen.

I can help you with that, if you want.

[goooseman]

@Rowno I see where the test fail, maybe the threshold is too low, I will update the test in a separate PR

[Rowno]

Odd, CI should be running for pul requests 🤔

[goooseman]

@Rowno creating a PR with test fix + CI config right now